Modified approach for apoptosis detection reveals changes in apoptotic processes in the seminoma-associated tissue

Apoptosis morphology (DNA condensation) and internucleosomal DNA cleavage ( TdT assay) were measured simultaneously on double fluorescence labeled test is tumor sections, employing conventional immunofluores cence microscopy. S ix different apoptosis indices (AI) were determined based either solely on morphological or biochemical criteria, or on a combination of both processe s. Measurements were performed in metastasized and non-metastasized seminom a, and in histological regions located distantly and associated with the tu mor. Preliminary results on 19 histologies revealed that up to 66% of apopt otic cells were not detected, depending on the method used for apoptosis de tection. Besides, no changes of solely morphologically defined AI was found in the different histological regions. By contrast, significant changes (p < 0.0004) in the different histological regions were detected when measuri ng AIs, e.g., defined by DNA fragmentation occuring without DNA condensatio n in apoptotic cells. Those changes were not detected in metastasized semin oma. These data, for the first time allow a comparison of two widely used a pproaches for apoptosis detection. Furthermore, the results reveal differen ces in apoptotic processes in tissue associated with non-metastasized semin oma detectable by a modified evaluated TdT assay but not by morphological c hanges, although this TdT method fails to show the total amount of apoptoti c cells.